Son Doong Cave in the central province of Quang Binh. Photo courtesy of Oxalis

'Son Doong is an invaluable natural resource that needs to be preserved.'

Vietnamese people have been signing up to an online petition in their droves to stop the construction of a cable car system into the world’s largest cave in the central province of Quang Binh, although local authorities have denied rumors of the project.

Information has been spreading rapidly on social media that Quang Binh has approved the cable car project into Son Doong, and that construction will start in February.

An online petition called “Stop Cable Car Construction to Son Doong Cave” said the provincial government has given FLC Group permission to conduct surveys for the construction of a cable car system into Son Doong. The petition was launched on Tuesday morning and has already received 8,200 supporters.

Tran Tien Dung, vice chairman of Quang Binh, told VnExpress that the province has no plans to build a cable car into the cave.

Nguyen Van Ky, deputy director of the provincial tourism department, said it is only calling for investors to look into cable car projects around the Phong Nha – Ke Bang National Park, which has been recognized by UNESCO as a world natural heritage site and is home to Son Doong.

“Son Doong is an invaluable natural resource that needs to be preserved,” Ky said.

A VnExpress source said the province has invited conservationists, including UNESCO experts, to the area to assess the environmental impacts of cable cars, which the province plans to use to draw more tourists to its long cave network.

The strong online protest is likely rooted from a controversial move more than two years ago when Quang Binh leaders pledged to build a $212-million gondola lift into Son Doong, ignoring environmental concerns.

They also named real estate giant Sun Group as the developer. However, the project received such strong criticism from the public, UNESCO and other international organizations that it never got off the ground.

Son Doong was opened to tourists in 2013, four years after members of the British Cave Research Association finished their exploration and named it the world’s largest cave.

The five kilometer-long system, which is 150 meters high and 200 meters wide, has at least 150 individual caves, a dense subterranean jungle and several underground rivers.

The cave is now a big attraction with huge interest from global media agencies and film studios. U.S. magazine Smithsonian in 2015 named it the greatest place to visit in the 21st century.

Quang Binh has increased the limit on the number of explorers allowed to visit Son Doong from 640 last year to 840 this year. The cave tour is always fully booked months ahead.